What is Logic?

What is Logic?

This is the homepage of my draft textbook, What is Logic?. The DRAFT status of this book is very important: Portions of it are substantially incomplete. If, however, you find any errors, please let me know.

There is a supplementary series of youtube videos covering content in this book.

Recent updates:

• 2025-04-09: Uploaded draft 2025-04-09, which removes an obviously unprovable “derivation” from Exercise 73, and added Exercise 95.
• 2025-02-03: Uploaded draft 2025-02-03; this version adds references for the DeMorgan quote in Chapter 6.
• 2024-04-04: Uploaded draft 2024-04-04; this version adds Section 10.6.